Duplicating machines



March 24, 1959 E. A. TOMLIN 2,378,750

DUPLICATING MACHINES Filed Oct. 8, 1953 v 3 Sheets-Sheet 1 ATTOB/VEY March 24, 1959 E. A. TOMLIN 2,878,750

DUPLICATING MACHINES Filed Out. 8, 1955 3 Sheets-Sheet 2 March 24, 1959 E. A. TOMLIN 2,878,750

' DUPLICATING MACHINES Filed Oct. 8, 1953 s Sheets-Sheet :5

ni SP efl -O DUPLICATING MACHINES Edward Albert Tomlin, Southgate, England, assignor to Gestetner Limited, London, England, a British company Application October 8, 1953, Serial No. 384,982

Claims priority, application Great Britain September 4, 1953 3 Claims. (Cl. 101-116) This invention concerns duplicating machines, more particularly machines in which a stencil travels around atop and bottom cylinder and the sheets of paper are fed in succession between the bottom cylinderand a pressure roller which presses the sheets against the travelling stencil, the sheets being delivered from between the bottom cylinder and the pressure rollers to a tray or'platform to build up a stack of copies thereon. As the copy tends to stick to the stencil stripper blades have hitherto been provided to engage each sheet as it is delivered. The pressure roller is mounted for oscillating movement towards the bottom cylinder so that it presses the sheets against the stencil and, at the appropriate time, awayirom the cylinder to clear means holding asilk screen and the stencil in position around the cylindersf As the stripper blades must also clear said holding means they have beensupported for movement with the. pressureiroller mechanism.

This known arrangement is open to several .disade vantages. .Firstly,.the pressure roller is moved against thebottom cylinder at a high speed andon impact the stencil is temporarily compressed so that the roller has Patented M 4 12 Figure 2 is a view similar to Figure 1 showing a part of the machine to a larger size and with a cover plate re: moved to show certain of the details of the machine;

Figure 3 is a view, partly in section, in the directioriof the arrow 3 of Figure 2; I

Figure 4 is a side view showing a detail of construction of the mechanism of Figure 2, and to a larger size, and

Figure 5 is a view similar to Figure 4 and showing the mechanism in another operative position.

Referring to Figure 1, the machine comprises a frame v 5 supported on a base 6, a platform 7 upon which a stack 8 of paper is placed to be fed through the machine, a delivery platform 9 upon which the stack 10 of copies is built on delivery of the copies from the machine, a top cylinder 11, a bottom cylinder 12, a pressure roller13; and means, generally indicated at 14, which passes around cylinders 11, 12 and to which there it secured a silk screen and a stencil for movement around the cylinders in any well known manner. The copies are delivered from the machine on to the stack 10 against a stop 15 carried by the platform 9. The machine is driven by a handle 16 mounted on a shaft 17 which carries a spur gear 18 meshing with a pinion 49 supported on the shaft of the bottom cylinder 12.

The sheets of paper are fed into the machine in conventional manner to between the bottom cylinder 12 and the pressure roller 13. The latter is supported upon a bar 19 which is oscillated by a mechanism (not shown but of conventional construction) whereby the roller 13 is moved towards and away from the bottom cylinder 12. The silk screen and stencil referred to are secured to the means 14 by bars and plates which project beyond the" afurther, and indeterminate, travel, the strippers per-v equivalent distance further away from the. stencil...andi 1 their. effectiveness isreduced. .Thirdly, .saidl further dis-.. tance which the strippers are held away from thestencili will; vary with the thickness of the paper or cardbeingifed through the machine.

- vThe object ofthis invention is the'provi'sion' ofalstrip per mechanism in which the disadvantages yreferred .to are reduced or overcome and this is achieved by: providing a mechanism to actuate the strippers which. is separate ofrthe mechanismactuating the pressure roller...

v A further disability associated with known/stripper mechanisms is that if. a sheet of paperbeing fed through.

thetmachine .is caught up with the. strippers .the stencil is, liable to be completely destroyed, oratleast, badly torn, since the stripper blades are held'against" mogernent ex:

" stripper mechanism comprises a bar 25 cept when the pressure roller is moved away from ,the

bottom cylinder. Another objectofthe invention is the provision of a stripper mechanism in which su clr tendency is minimised, if not eliminated.

,The means in which these I iriyention are attained in practice will be understood from the f ollowing description of a duplicating machine, which is igiven by way of example only, made with reference tome-accompanying drawings whereof: Figure 1 is a diagrammatic side view of adupli cating matinee in accordance withthe"presentinventioiif and other objects ofithe outer face of the stencil and the roller 13 is oscillated as indicated to clear such projections. When a sheetof paper from the stack 8 is fed on to the stencil the roller 13 is brought into engagement with the paper to press it against the stencil. The mechanism for oscillating the roller 13 does not form part of the present invention and is therefore not described in detail. A member, generally indicated by the reference numeral 20, is hooked over the bar 19 and comprises a springclip21 to engage -a spindle 22 bywhich the memberis supported immediately in front of the region in which the copies are delivered from between the cylinder 12;": The member 20 comprises a pair of spaced,- upwardly inclined guides 23 against which the copies are fed, the copies being directed upwardly along the guides and over. the top edge 24 thereof. It will be evident that the mem ber 20 is readily disengaged from the spindle 22 and may then be unhooked from the bar 19. f As shown in Figure 3 the member 20 is centrally disposed of the cylinders 11 and 12. There is provided a stripper mechanism to ensure that" the copies, which have a tendency to stick to the stencil, disengage the stencil immediately after they are delivered from between the cylinder 12 and the roller 13. The (Figure 3 'sup{ ported in bearings 26, 27 carried by the frames 5 of the machine, and a pair of stripper blades 28 supported'from' the -bar 25. The blades have inclined ends, as at 50' (Figure 2) the ends being adapted to approach the cylinf' der '12 at a tangent. As more clearly shown in Figure 3 the blades 28 are mounted on blocks 29 whichcarry knurled nuts 30 for securing the blocks against movement to the bar 25. When the knurled nuts are releasedthe blocks,-and. the stripper blades 28, are capable of ad justment lengthwise'of the bar, i.e. lengthwise .of the cylinder 12 and across the width of the sheet of paper. One end of the bar 25 carries a lever 31 having a pin 32 (Figure 2) which enters a slot 33 in a rocking member- 34'which is pivotally supportedat' 35, As the member rocks, the engagement of the pin 32a'nd the slot 33'res'u1ts .7 '3 in the bar 25 being oscillated so that the stripper blades 28 are adjusted from the full line position to the chaindotted position shown in Figure 2. A cam 36 is mounted on shaft 17 and is engaged by a cam follower 37 carried by leyer 38, the follower being held in engagement with the cam by a spring 39. The cam imparts a rocking movement to the member '34.

The bearing 26 comprises a casing 40, a plunger 41 within the casing and a spring 42 urging the plunger 41 towards the left as seen in Figure 3. The end of the casing 46 has a hole to receive the rounded part 43 of the bar 25. When the bar 25 is forced to the right to cornpress the spring 42 the bar can disengage the bearing 27 and be taken out from the machine.

I In use a sheet of paper as it is delivered from between the cylinder 12 and the roller 13 is engaged on its upper surface and at its forward edge, by the blades 28 which strip the copy from the stencil, the copy being forced to travel beneath the stripper bladeswhich therefore engage the upper surface of the copy towards the marginal edges thereof as shown in Figure 3. After the leading edge of the copy is stripped from the stencil, it engages the guide 23 and is carried up and over the top 24 thereof. The guide 23 engages the under surface of the paper between the blades 28 and it will be seen from Figure 3 that the top edge 24 of the guide 23 is vertically above the stripper blades 28 with the consequence that the copy is bowed about an axis parallel with the direction of travel of the sheet, the concave surface being downwardly directed. As a consequence of the bowing there is imparted to the sheet a certain rigidity which ensures that it is carried above the stack until the leading edge of the sheet strikes the stop whereupon the copy descends on to the stack and there is therefore no risk of the ink on the topmost copy of the stack being smudged upon the delivery of the next succeeding copy. The bowed sheet is shown at x in Figure 3 v The purpose of oscillating the blades 28 is to ensure that, as also is required in the case of the pressure roller 13, they clear the projections of the means 14 which secure the silk screen and stencil to the cylinders 11 and 12.

, The blades 28 are required closely to approach the stencil but not to engage therewith and in Figures 4 and 5 there is shown means for adjusting the extent of oscillation of the blades towards the lower cylinder 12 for this purpose. An outer face cam 55 pivotally carried, at 56, on member 34 and lockable against movement by screw 57 engages pin 32. Figure 4 shows cam 55 in its fully raised position and with the lowermost part of its cam face engaged by pin 32 so that the pin may enter fully into the slot in member 34 whereby blades 28 are raised to their greatest extent-as shown. In Figure 5 cam 55 has been adjusted so that the highest part of its cam face will be engaged by pin 32 which is consequently prevented from fully entering the slot of member 34 with the result that the blades 28 are held off to some extent from cylinder 12 as shown in Figure 5.

As the blades 28 may be swung away from the stencil, the cam follower 37 being thereby moved away from cam 36 against the action of spring 39, if a sheet of paper is inadvertently brought between the blades and the stencil, orif an obstruction is encountered by the blades when oscillating them towards the stencil, it is ensured that the blades resiliently ride over the sheet of paper or the obstruction.

Since the pressure roller 13 is oscillated by its mechanism (not shown but of conventional construction) while the stripper blades 28 are independently actuated by cam 36, follower 37, lever 38 and rocking lever 34 it is ensured that the strippers are brought close to the stencil but that the nearest position of the stripper blades is not varied by impact of the pressure roller with the bottom cylinder 12. In other words, when the stripper blades have been adjusted to a particular operating condition (allowing, for instance, forthe thickness of the paper currently being used and of the stencil) while these conditions obtain the stripper blades will not come closer to the stencil with variations in operation of the pressure roller. Furthermore, if a sheet of paper being fed through the machine is caught with the stripper blades the latter will be pushed away from the bottom cylinder against the action of spring 39 and, in most cases the damage to the stencil is prevented.

An advantage of the arrangement described is that the stripper mechanism comprising bar 25, blades 28, lever 31 and pin 32 are readily removable from the machine by moving 'bar 25 to compress spring 42 and thereby disengage the bar from bearing 27.

I claim:

l. A duplicating machine comprising a frame; a stencil-carrying cylinder rotatably mounted in the frame; means carried around with the cylinder for securing a stencil to the cylinder; an oscillatable mounting and a pressure roller carried thereby, whereby the pressure roller is movable towards and away from said cylinder to clear said stencil-securing means; a bar pivotally secured to the frame; at least a pair of blades carried by the bar for stripping copies from the cylinder; a rocking member rotatably mounted in said frame about an axis spaced from the pivot axis of the bar; a pin and slot connection between said rocking member and said bar, movement of said pin in said slot, when the rocking member is stationary, varying the angular relationship between said bar and said rocking member and thus varying the shortest distance between the blades and the cylinder; means for adjusting the position of said pin in said "slot; and means,- movable independently of said oscillatable mounting, for oscillating said rocking member and thereby moving the stripper blades towards and away from the cylinder to clear the stencil-securing means.

2. A duplicating machine comprising a frame; a stencil-carrying cylinder rotatably mounted in the frame; means carried around with the cylinder for securing a stencil to the cylinder; an oscillatable mounting and a pressure roller carried thereby, whereby the pressure roller is movable towards and away from said cylinder to clear said stencil-securing means; a bar pivotally secured to themachine frame; at least a pair of blades carried by the bar for stripping copies from the cylinder; a rocking member rotatably mounted in said frame about an axis spaced from the pivot axis of the bar; a pin and slot connection between said rocking member and said bar, movement of said pin in said slot, when the rocking member is stationary, varying the angular relationship between said bar and said rocking member and thus varying the shortest distance between the blades and the cylinder; a cam for adjusting the position of said pin in said slot; and means, movable independently of said oscillatable mounting, for oscillating said rocking member and thereby moving the stripper blades towards and away from the cylinder to clear the stencil-securing means.

3. A duplicating machine comprising a frame; a stencil-carrying cylinder rotatably mounted in the frame; means carried around with the cylinder for securing a stencil to the cylinder; an oscillatable mounting and a pressure roller carried thereby, whereby the pressure roller is movable towards and away from said cylinder to clear said stencil-securing means; a bar pivotally secured to the machine frame; at least a pair of blades carried by the bar for stripping copies from the cylinder; a slotted rocking member rotatably mounted in said frame about an axis spaced from the pivot axis of the bar; a pin mounted in theslot of said rocking member and connected tos aidbar, movement of the pin in the slot when the rocking member is stationary varying the angular relationship between the bar and the rocking member and thus varying the shortest distance between the blades and the cylinder; a cam movably mounted on said rocking member and engaging said pin; movement of said cam adjusting the position of the pin in the slot; means for locking said cam to said rc-cking member; and means, movable independently of said oscillatable mounting, for oscillating said rocking member and thereby moving the stripper blades towards and away from the cylinder to clear the stencil-securing means.

6 References Cited in the file of this patent UNITED STATES PATENTS Wood July 25, 1911 Harding Sept. 26, 1933 Creed Nov. 7, 1933 Brasseur June 26, 1934 Brown Aug. 20, 1940 FOREIGN PATENTS France Nov. 15, 1921 

